You've also opened yourself up to an insurance liability in the event of a collision by removing/disabling ABS in an ABS equipped vehicle. Not something that should be done on a street truck, IMO.
Brake pads for 93 Land Cruiser
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Wow, glad I checked this thread out. Since I've been running larger tires (315/75 - 16s) was thinking of running the 100 pads. Previously read on mud that they were better. Currently running Napa ceramic 80 pads....think I'll just replace with same.
Nope. A larger swept area gives more braking force. Obviously, any part of the pad hanging off the outside of the disc doesn't count toward the swept area.
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Within reason, the size of the pad has nothing to do with braking power.
Yeah it does. Google "swept area".
Someone drank the koolaid.
The Koolaid of physics. More surface area means more friction, which means more braking.
If you don't believe me, pull your front pads and use a grinder to remove all but one square inch of material and see how good your braking is.
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Do a bit of brake design reading, there is much BS in brake advertising. The hydraulic pressure puts, x pressure on the pads, pads clamp on the rotor, big or small pads, the total clamping force is the same. Small pads will have higher psi over the pad surface, higher pad temp/wear rate, larger pads will have lower psi over the pad surface, higher rotor temp/lower pad wear. Both have the same clamping force, if the coefficient of friction is the same, the brake effectiveness will be the same. The difference we are talking about here is small, only nets slightly longer pad life.
Do you also believe that red calipers are the best performing, what hue have you found to be the most effective?
I am partial to the rust colored ones that have a powder coating of brake dust.Do you also believe that red calipers are the best performing, what hue have you found to be the most effective?
Nothing I said has anything to do with "brake advertising". In fact, I don't think I've ever seen a brake manufacturer say a word about swept area with regards to pads.
The same clamping force applied to a larger area yields more friction, period.
What's the point of this sort of asinine comment? Do you think it aids your argument in any way? I think maybe *you* need to go do some studying, and stop assuming that anyone who disagrees with you is getting their information from "brake advertising".
So, to you as well, go ahead and prove it to the world: grind your pads down to one square inch of material and show us that your breaking is the same. Once you've done that, manufacturers around the world will be delighted to know that they can make their brake pads arbitrarily small, since they have the same clamping force.
You would benefit from doing as Kevin suggested and do some research before continuing this argument. What you say seems intuitive, but you're missing some key knowledge. This whole concept is not as simple as it seems, but when you get into a discussion with someone who knows his s***, it's better to go into it not believing you know it all and look for the opportunity to learn something. Maybe you'll end up proving your point, who knows?
Let’s go about this in a more scientific way, here is the formula for friction:
This equation tells you that when you have the normal force, FN, all you have to do is multiply it by a constant to get the friction force, FF. This constant,
is called the coefficient of friction, and it’s something you measure for contact between two particular surfaces. (Note: Coefficients are simply numbers; they don’t have units.)
You may notice the formulas doesn’t contain surface area however it is for a set surface area, example would be 1 square inch. The force due to friction is generally independent of the contact area between the two surfaces. This means that even if you have two heavy objects of the same mass, where one is half as long and twice as high as the other one, they still experience the same frictional force when you drag them over the ground. This makes sense, because if the area of contact doubles, you may think that you should get twice as much friction. But when you double the length of an object, you halve the force on each square centimeter, because less weight is above it to push down. Note that this relationship breaks down when the surface area gets too small, since then the coefficient of friction increases because the object may begin to dig into the surface.
So in conclusion within the limit of coefficient( brake pad material design) increasing the surface area(larger brake pad) without increasing force(brake caliper force applied to the pads) the overall friction won’t change. If surface area is increased too much then you will lose friction because not enough force is there to achieve optimum coefficient (highest friction before material breaks down/wear out too fast) which is only achieved at certain temperature which is achieved by having enough friction. This is why carbon ceramic racing brakes feel like skates unless heated up.
Here is a side by side comparison of the 2pads even thought it doesn’t make any difference unless material is different:
80 vs. 100 series brake pads: Picture
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DB1365 105 series pads will fit without using any pad shims in the calipers for the larger front brakes.
So as long as FN remains constant...size doesn't matter.
As much as it pains me, I have to agree with Kevin on this one. Overall braking effect will not change with a larger pad unless the clamping force changes. If you redesign the system, then you will get improved performance. Vehicle brakes are a system, not just a bunch of parts.
We actually did this back in a mechanics class back in college (I'm old, so this was a long time ago). We shaved down a brake pad to be about 1/2 the normal area and measured the braking torque as compared to a full size pad. Whaddya know! The physics presented by @Qball, above, actually work. (surprise...) Braking torque applied was essentially the same as with a full size pad. Science!
So why are bigger brakes with larger swept area an advantage? Heat. As in the ability to efficiently absorb and dissipate the heat so things don't melt.
So yes, while a smaller pad will have the same frictional force and braking power as the larger one, it can't dissipate the heat as well because there's less stuff to soak up the heat and less area for cooling to take place. Initial braking power is the same, but smaller pads have less resistance to fade and ultimately, catastrophic heat disintegration. Also, because the smaller pad has to accomplish the same amount of kinetic energy to thermal energy conversion (that's what braking is, after all), it'll wear out much faster. In that same experiment, the smaller pad started smoking and fading much earlier than the full size pad when we ran each to their functional limit (red hot rotor, lots of smoke - we did this outdoors.)
Swept area is more about heat management and wear rather than peak braking force. Race cars have big brakes only because they have a lot of heat to dump, and need the equipment to last (not fade, burn or melt) almost continuously.
As a side note. We also studied why bigger tires (and their correspondingly bigger contact patches) are NOT the same as a brake pad on a rotor. Whereas brake pads on a smooth (ish) rotor are pretty close to the classic mechanical physics friction problem, tires on pavement is NOT. The conformability of the rubber into the irregular surface of pavement really changes the behavior of "grip". (And I say grip instead of friction there because there's much more than friction at play there.)
Back to our trucks - I've never had to worry about brake fade with either stock or 100-series pads (I've used both). When I used to run cars on the track, finding brakes that would withstand the heat and not fade was a major challenge.
So why are bigger brakes with larger swept area an advantage? Heat. As in the ability to efficiently absorb and dissipate the heat so things don't melt.
So yes, while a smaller pad will have the same frictional force and braking power as the larger one, it can't dissipate the heat as well because there's less stuff to soak up the heat and less area for cooling to take place. Initial braking power is the same, but smaller pads have less resistance to fade and ultimately, catastrophic heat disintegration. Also, because the smaller pad has to accomplish the same amount of kinetic energy to thermal energy conversion (that's what braking is, after all), it'll wear out much faster. In that same experiment, the smaller pad started smoking and fading much earlier than the full size pad when we ran each to their functional limit (red hot rotor, lots of smoke - we did this outdoors.)
Swept area is more about heat management and wear rather than peak braking force. Race cars have big brakes only because they have a lot of heat to dump, and need the equipment to last (not fade, burn or melt) almost continuously.
As a side note. We also studied why bigger tires (and their correspondingly bigger contact patches) are NOT the same as a brake pad on a rotor. Whereas brake pads on a smooth (ish) rotor are pretty close to the classic mechanical physics friction problem, tires on pavement is NOT. The conformability of the rubber into the irregular surface of pavement really changes the behavior of "grip". (And I say grip instead of friction there because there's much more than friction at play there.)
Back to our trucks - I've never had to worry about brake fade with either stock or 100-series pads (I've used both). When I used to run cars on the track, finding brakes that would withstand the heat and not fade was a major challenge.
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Let’s go about this in a more scientific way, here is the formula for friction:
This equation tells you that when you have the normal force, FN, all you have to do is multiply it by a constant to get the friction force, FF. This constant,
is called the coefficient of friction, and it’s something you measure for contact between two particular surfaces. (Note: Coefficients are simply numbers; they don’t have units.)
You may notice the formulas doesn’t contain surface area however it is for a set surface area, example would be 1 square inch. The force due to friction is generally independent of the contact area between the two surfaces. This means that even if you have two heavy objects of the same mass, where one is half as long and twice as high as the other one, they still experience the same frictional force when you drag them over the ground. This makes sense, because if the area of contact doubles, you may think that you should get twice as much friction. But when you double the length of an object, you halve the force on each square centimeter, because less weight is above it to push down. Note that this relationship breaks down when the surface area gets too small, since then the coefficient of friction increases because the object may begin to dig into the surface.
So in conclusion within the limit of coefficient( brake pad material design) increasing the surface area(larger brake pad) without increasing force(brake caliper force applied to the pads) the overall friction won’t change. If surface area is increased too much then you will lose friction because not enough force is there to achieve optimum coefficient (highest friction before material breaks down/wear out too fast) which is only achieved at certain temperature which is achieved by having enough friction. This is why carbon ceramic racing brakes feel like skates unless heated up.
Here is a side by side comparison of the 2pads even thought it doesn’t make any difference unless material is different:
80 vs. 100 series brake pads: Picture
First, I am NOT an engineer, so bear with me as I try to wrap my head around this.
Assumed Constants:
pedal pressure=100 LB. (Not a real number, just used for reference)
80 series pads area = 6 sq.in. (Not a real number, just used for reference)
100 Series pads area = 8 sq. in. (Not a real number, just used for reference)
Coefficient of friction = some constant number
If I use the 80 series pads and push on the pedal at 100 PSI, I get 16.67 PSI force on the pad.
If I use the 100 series pads and push on the pedal at 100 PSI, I get 12.56 PSI force on the pad.
So, because I have INCREASED the surface area, I have REDUCED the PSI (Assuming the same pedal pressure) in contact with the rotor. Then, I factor friction into it, since I actually have LOWER PSI on the larger pad, I have LESS braking?
Does the coefficient of friction remain constant between these two, assuming the same materials of construction?
But even though I have more surface area in contact with the rotor, wouldn't I have more TOTAL friction?
I guess I'm relating it to hydraulic pressure transfer like with hydraulic cylinders. If you have a larger surface area within the cylinder and a given pressure, what changes is the speed.
Hep me out, as I must be missing something.
For another source on this:
Brake System and Upgrade Selection
Brake System and Upgrade Selection
the best way to look at is that formula is only applied to a set surface area. Let's say brake force is 100 and coefficient is 100 for 1 square inch which gives us break force of 1000 for that 1 square inch.
100 X 100 = 10000(total friction)/1 = 10000 per square inch
If you change surface area to 2 then it becomes:
100 x 100 = 10000(total friction)/2 = 5000 per square inch
So by increase surface area from 1 to 2 square inch without increase pressure then you are effectively reducing the amount of friction per square inch by half or didn't change the overall brake force at all just like your calculation have concluded.
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